Q&A - PSLE Math

[elkniwt]

Dear tianzhu,


Firstly, thank you very much for your help time and again. Really appreciate.

My dd encountered this qn from her school worksheet. It goes :
Q1) A taxi driver charges $2.60 for the first km and 10c per additional 195m. How much must a passenger pay for a journey of 12km?
She got the answer $8.30 [$2.60 for first km + 57 x 10c for the remaining distance]. She was marked wrong. Her teacher explained that since there is no "part thereof" in the question, the extra 80m which is less than 195m should be excluded. Teacher’s answer is $8.20 [$2.60 + 56 x 10c]

Then she encountered another question from Rosyth paper.
Q2) The table below shows the airmail rates to America.
First 20g -> $1.10
Additional 10g -> $0.35
Find the cost of airmail which weighs 29g.

Her answer is $1.10 (since there is no part thereof in the question).
This time, the answer given is $1.45 [$1.10 + 1 x $0.35] .

Hence, both of us are baffled. ???

[tianzhu]

Hi elkniwt


You’re welcome.

Please refer to MathIzzzFun’s post below.

Best wishes

[MathIzzzFun]

elkniwt:

Dear tianzhu,


Firstly, thank you very much for your help time and again. Really appreciate.

My dd encountered this qn from her school worksheet. It goes :
Q1) A taxi driver charges $2.60 for the first km and 10c per additional 195m. How much must a passenger pay for a journey of 12km?
She got the answer $8.30 [$2.60 for first km + 57 x 10c for the remaining distance]. She was marked wrong. Her teacher explained that since there is no \"part thereof\" in the question, the extra 80m which is less than 195m should be excluded. Teacher's answer is $8.20 [$2.60 + 56 x 10c]

Then she encountered another question from Rosyth paper.
Q2) The table below shows the airmail rates to America.
First 20g -> $1.10
Additional 10g -> $0.35
Find the cost of airmail which weighs 29g.

Her answer is $1.10 (since there is no part thereof in the question).
This time, the answer given is $1.45 [$1.10 + 1 x $0.35] .

Hence, both of us are baffled. ???

Hi

the teachers are right.

1) for taxi meter, fares are paid according to distance travelled ie if the distance travelled is 1km 190m then the fare is just starting fare ie $2.60 in this case. The fare will increase to $2.70 at 1195m.

2) for air mail, rates are charged according to how heavy each package weighs.. so additional 10g would actually means \"up to additional 10g\".

cheers.

[tianzhu]

Hi


Good Morning.

I’ve a question from a member via PM. It’s about fried noodle and bak chor mee, but I am changing it to fried rice because I only have a photograph of fried rice.

This question is similar to the “Counting heads and legs” type of question but with a tweak. One needs to work in groups of 3 children in this particular case.

Besides GC, you may use “Make a Supposition” or Assumption Method”.

Pretend, Pretend lah,
Start with suppose, assume or pretend all were adults.

Hope this helps.

Best wishes

http://farm8.staticflickr.com/7022/6518324819_548ca9d2dc_z.jpg\">

[elkniwt]

Dear tianzhu and MathIzzzFun,


My sincere appreciation!!! Thank you both very much!

[small]

Brain stuck, please help and TIA..


A car and a loory started at the same time and travelled from Town R to Town S along the same route, When the car arrived in Town S 45 min ealier than the lorry, the lorry had only just travelled 3/5 of the journey. If the averagespped of the lorry was 60 km/h, find the distance between the two towns.

[MathIzzzFun]

small:

Brain stuck, please help and TIA..


A car and a loory started at the same time and travelled from Town R to Town S along the same route, When the car arrived in Town S 45 min ealier than the lorry, the lorry had only just travelled 3/5 of the journey. If the averagespped of the lorry was 60 km/h, find the distance between the two towns.

Hi

The car reached Town S 45 min earlier which also means that the lorry will take another 45 min to reach Town S ... speed of lorry is known, so the distance to Town S can be calculated and this is equal to 2/5 of the journey.. I think you complete the solution

cheers.

[small]

MathIzzzFun:

small:

Brain stuck, please help and TIA..


A car and a lorry started at the same time and travelled from Town R to Town S along the same route, When the car arrived in Town S 45 min ealier than the lorry, the lorry had only just travelled 3/5 of the journey. If the average speed of the lorry was 60 km/h, find the distance between the two towns.

Hi

The car reached Town S 45 min earlier which also means that the lorry will take another 45 min to reach Town S ... speed of lorry is known, so the distance to Town S can be calculated and this is equal to 2/5 of the journey.. I think you complete the solution

cheers.

Hi MathIzzzFun,

Thanks for the solution..

By the way, can you please explain why the lorry will also take another 45 min to reach Town S if the speed of the 2 vehicles not the same?

[tianzhu]

Hi small


Good Morning.

Hope this helps.

Best wishes

http://farm8.staticflickr.com/7146/6578211687_96541f06a3_z.jpg\">

[small]

tianzhu:

Hi small


Good Morning.

Hope this helps.

Best wishes

http://farm8.staticflickr.com/7146/6578211687_96541f06a3_z.jpg\">

lol, my son and I think too much.

Anyway Tianzhu & MathIzzfun, once again many thanks for your help.